Thermal energy storage systems incorporating phase change material are well known in the art. Such systems generally include a tank containing the phase change material. Thermal energy, when added to the phase change material, causes the phase change material to absorb at least some thermal energy in an amount equal to its heat of fusion and accordingly change phase from solid to liquid. Thermal energy, when removed from the phase change material, causes the phase change material to release its heat of fusion and accordingly change phase from liquid to solid.
In prior art thermal energy storage systems, generally one or more heat exchangers submerged within the phase change material are used for adding and/or removing the thermal energy. As is well known in the art, removal of thermal energy from the phase change material causes the phase change material to solidify on the heat exchanger surfaces and consequentially deteriorates the heat exchanger effectiveness.
Accordingly, there exists a need for a thermal energy storage system wherein the phase change material does not solidify on one or more heat exchangers as the phase change material releases its heat of fusion in the form of thermal energy extracted from the thermal energy storage system.